[An attempt to predict the noise-induced PTS. Beginning a long-time study (author's transl)]

After the exposure to a sinus-tone of 250 cps the audiogram shows two dips: the first in the low-frequency-range, the second at about 5 kcps. In noise-resistant men (having normal hearing in spite of having worked in noise for many years) the TTS in the high-frequency-range is significantly smaller than in the average of the population. Therefore this depression is to be used for a tentative prognosis of PTS. The test is done with frequency-constant Békésy-audiometry before and after the exposure to a sinus-tone of 250 cps (120 dB HL) for 10 min. Attention is payed to TTS2 as well as to the alteration of the altitude of the spikes and also to the reconstitution of both of them. A decision on the usefullness of this test for the prognosis could be expected in about two or three years.